Create normals and actually use texture
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2 changed files with 76 additions and 29 deletions
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@ -1,12 +1,12 @@
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//
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// This source code is property of the Computer Graphics and Visualization
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// chair of the TU Dresden. Do not distribute in modified or unmodified form!
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// This source code is property of the Computer Graphics and Visualization
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// chair of the TU Dresden. Do not distribute in modified or unmodified form!
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// Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
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//
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/*************************************************************************
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Terrain.
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This class represents a textured and shaded terrain. Both, the texture
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and the height map is read from a bmp file (in the constructor).
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and the height map is read from a bmp file (in the constructor).
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The height map is mapped to a regular grid consisting of triangle strips.
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During rendering the normals needed for lighting are calculated.
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There are some additional rendering modes:
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@ -18,7 +18,7 @@ The rendering is done in the "render" method which sets the projection
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and view via "setup_projection" and the light via "setup_light".
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Depending on the settings (that can be changed using "set_show_solid",
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"set_show_wireframe" and "set_show_levels") different passes are rendered
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using the appropriate rendering method ("render_solid_terrain",
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using the appropriate rendering method ("render_solid_terrain",
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"render_wireframe_terrain", "render_level_lines"). They call the
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"render_terrain" method.
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*************************************************************************/
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@ -92,7 +92,10 @@ private:
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// Create height lines for the level "level"
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void create_level_line(int level);
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void push_point(int x, int y);
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vec3d create_point(int x, int y);
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vec2d texture_coord(int x, int y);
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// Load the height map from the file "filename"
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bool load_heightmap(const char *filename);
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// Return the width of the height map
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@ -1,6 +1,6 @@
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//
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// This source code is property of the Computer Graphics and Visualization
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// chair of the TU Dresden. Do not distribute in modified or unmodified form!
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// This source code is property of the Computer Graphics and Visualization
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// chair of the TU Dresden. Do not distribute in modified or unmodified form!
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// Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
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//
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#include "terrain.h"
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@ -112,8 +112,9 @@ void terrain::render_solid_terrain()
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glEnable(GL_TEXTURE_2D);
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glActiveTexture(GL_TEXTURE0);
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glBindTexture(GL_TEXTURE0, texture_handle);
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// Set the material color to white
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glColor3d(1, 1, 1);
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@ -123,7 +124,7 @@ void terrain::render_solid_terrain()
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// Disable texture mapping
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glDisable(GL_TEXTURE_2D);
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// Disable support for depth buffer offsets
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glDisable(GL_POLYGON_OFFSET_FILL);
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glDisable(GL_POLYGON_OFFSET_FILL);
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// Disable lighting
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glDisable(GL_LIGHTING);
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}
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@ -141,13 +142,18 @@ void terrain::render_wireframe_terrain()
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// Set the color to black
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glColor3d(0, 0, 0);
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// Render the terrain
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render_terrain();
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render_terrain();
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// Set the draw mode to fill polygons
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glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
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}
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void terrain::push_point(int x, int y)
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{
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set_normal(x, y);
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glTexCoord2dv(texture_coord(x, y));
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glVertex3dv(create_point(x, y));
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}
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// Render the terrain
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void terrain::render_terrain()
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@ -175,7 +181,7 @@ void terrain::render_terrain()
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and translated to use the values of the variables "x" and "y"
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defined below directly as coordinates. The initial height of
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the grid shall be 0.
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Aufgabe 2.2.1. Vervollstaendigen Sie den nachfolgenden Quelltext um die
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Aufgabe 2.2.1. Vervollstaendigen Sie den nachfolgenden Quelltext um die
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Erstellung eines regelmaessigen Gitters das sich ueber die
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X-Z-Ebene erstreckt. Erstellen Sie dieses Gitter, indem Sie
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zeilenweise Dreiecksstreifen definieren. Das Koordinatensystem
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@ -184,23 +190,23 @@ void terrain::render_terrain()
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als Koordinaten einsetzen koennen. Das Gitter soll zunaechst
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eine Hoehe von 0 besitzen.
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Task 2.2.2. Now elevate the height of the vertices to create the grid terrain
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that corresponds to the height map. Use "get_heightmap_value(x, y)".
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Aufgabe 2.2.2. Heben Sie jetzt die Vertices an um ein Drahtgitterterrain zu erstellen,
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das zur Hoehenkarte korrespondiert. Nutzen Sie die Methode
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das zur Hoehenkarte korrespondiert. Nutzen Sie die Methode
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"get_heightmap_value(x, y)".
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Task 2.2.3. Make sure to call "set_normal" for every vertex and continue this
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Task 2.2.3. Make sure to call "set_normal" for every vertex and continue this
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task in "set_normal".
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Aufgabe 2.2.3. Stellen Sie sicher, dass Sie "set_normal" f<EFBFBD>r jeden Vertex aufrufen
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und fahren Sie in "set_normal" mit der Aufgabe fort.
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Task 2.2.4. Activate texture mapping and bind the texture in the method
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Task 2.2.4. Activate texture mapping and bind the texture in the method
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"render_solid_terrain". Provide 2D texture coordinates per vertex in
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this method using "glTexCoord2d".
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this method using "glTexCoord2d".
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Aufgabe 2.2.4. Aktivieren Sie Texturmapping und binden Sie eine Textur in der
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Methode "render_solid_terrain". Spezifizieren Sie in dieser Methode pro
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Vertex eine Texturkoordinate mittels der Methode "glTexCoord2d".
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@ -214,8 +220,8 @@ void terrain::render_terrain()
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// Draw one strip
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for (int x = 0; x < map_width; x++) {
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glVertex3f(static_cast<float>(x), get_heightmap_value(x, y), static_cast<float>(y));
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glVertex3f(static_cast<float>(x), get_heightmap_value(x, y + 1), static_cast<float>(y) + 1.0f);
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push_point(x, y);
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push_point(x, y + 1);
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}
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glEnd();
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@ -224,8 +230,30 @@ void terrain::render_terrain()
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glPopMatrix();
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}
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vec2d terrain::texture_coord(int x, int y)
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{
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return vec2d(
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static_cast<double>(x) / static_cast<double>(get_heightmap_width()),
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static_cast<double>(y) / static_cast<double>(get_heightmap_height())
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);
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}
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vec3d terrain::create_point(int x, int y)
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{
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return vec3d(
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static_cast<double>(x),
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static_cast<double>(get_heightmap_value(x, y)),
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static_cast<double>(y)
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);
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}
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vec3d calculate_normal(vec3d middle, vec3d p0, vec3d p1)
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{
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vec3d v0 = middle - p0;
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vec3d v1 = p1 - middle;
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return cross(v0, v1);
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}
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// Calculate and set the normal for height map entry (x,y)
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void terrain::set_normal(int x, int y)
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@ -235,8 +263,8 @@ void terrain::set_normal(int x, int y)
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the height map value (x, y). You can either use forward differences,
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backward differences or central differences. The latter will give
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the best results. The calculation is done by first determining direction
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vectors in X and Z and then using vector operations to get a vector that
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is perpendicular to both. You find some examples for vector operations in
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vectors in X and Z and then using vector operations to get a vector that
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is perpendicular to both. You find some examples for vector operations in
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this project below. Do not forget to pass the normal to OpenGL using
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the command glNormal3d.
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@ -246,7 +274,7 @@ void terrain::set_normal(int x, int y)
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Fuer die Berechnung werden zunaechst Richtungvektoren in X- und Z-Richtung
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gebildet und anschliessend mittels Vektoroperationen ein zu beiden Vektoren
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senkrechter Vektor berechnet. Nachfolgend ein paar Beispiele fuer Vektor-
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rechnungen in diesem Projekt. Vergessen Sie nicht die Normale nach der
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rechnungen in diesem Projekt. Vergessen Sie nicht die Normale nach der
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Berechnung mittels glNormal3d an OpenGL zu senden.
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// Create a vector
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@ -270,6 +298,22 @@ void terrain::set_normal(int x, int y)
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double y = vec3.y();
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double z = vec3.z();
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*****************/
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vec3d middle = create_point(x, y);
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vec3d right = create_point(x + 1, y);
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vec3d top = create_point(x, y + 1);
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vec3d left = create_point(x - 1, y);
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vec3d bottom = create_point(x, y - 1);
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vec3d normal0 = calculate_normal(middle, right, top);
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vec3d normal1 = calculate_normal(middle, top, left);
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vec3d normal2 = calculate_normal(middle, left, bottom);
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vec3d normal3 = calculate_normal(middle, bottom, right);
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vec3d final_normal = (normal0 + normal1 + normal2 + normal3) / 4;
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glNormal3dv(final_normal);
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}
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@ -312,8 +356,8 @@ void terrain::render_level_lines()
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void terrain::create_level_line(int level)
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{
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/********
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Additional Task: Find iso lines with the "Marching Squares" algorithm for the
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height value "level". Store the start and end points of the
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Additional Task: Find iso lines with the "Marching Squares" algorithm for the
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height value "level". Store the start and end points of the
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found lines in the list "level_lines".
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Zusatzaufgabe: Finden Sie Hoehenlinien mittels des "Marching Squares"-Algorithmus
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fuer den Hoehenwert "level". Legen Sie die Start- und Endpunkte
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@ -350,7 +394,7 @@ void terrain::setup_light()
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glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse_color);
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glLightfv(GL_LIGHT0, GL_SPECULAR, specular_color);
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glLightf(GL_LIGHT0,GL_SPOT_EXPONENT, 10.0f);
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glLightf(GL_LIGHT0,GL_SPOT_EXPONENT, 10.0f);
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glPopMatrix();
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@ -403,7 +447,7 @@ void terrain::set_show_solid(bool state)
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void terrain::set_show_wireframe(bool state)
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{
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show_wireframe = state;
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// The current display list is outdated now
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// The current display list is outdated now
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dl_valid = false;
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}
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@ -442,7 +486,7 @@ bool terrain::load_heightmap(const char *filename)
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}
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// All went well...
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return true;
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return true;
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}
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@ -476,7 +520,7 @@ bool terrain::load_texture(const char *filename, GLuint *handle)
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// Clamp the texture at the borders
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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// Transfer the image data to the graphics card.
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, BMP_GetWidth(bitmap), BMP_GetHeight(bitmap), 0, GL_RGB, GL_UNSIGNED_BYTE, data);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, BMP_GetWidth(bitmap), BMP_GetHeight(bitmap), 0, GL_RGB, GL_UNSIGNED_BYTE, data);
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// Not needed anymore
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free(data);
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